For the first two decades of its existence, the Association of Southeast Asian Nations (ASEAN) had the field of inter-governmental regional bodies in East Asia and the wider Asia Pacific to itself. This suited ASEAN and its objective of engaging all extra-regional powers to help ensure none gains hegemony in Southeast Asia. (1) The last two decades have been very different, as East Asia and the wider Asia-Pacific regions have seen proliferation of Track-II, ministerial level and leaders-level regional organizations. The leaders-led organizations, ASEAN, Asia-Pacific Economic Cooperation (APEC), the ASEAN+3 process (APT) and the East Asia Summit (EAS), gain the greatest support from their leading members and attention globally. This proliferation seems to be accelerating as Australian Prime Minister Kevin Rudd recently called for new leaders-led Asia-Pacific Community. (2) US Secretary of State Condoleeza Rice has added her support to turning the ad hoc Six-Party Talks on North Korea into permanent Northeast Asian security institution. Japan has offered to host trilateral leaders' summit between Japan, China and South Korea in 2008, and this may turn into an annual, rotating event. (3) At the same time, influential non-official voices are suggesting the idea of setting up new leaders-led Asia-Pacific security forum to complement the confidence building work of the ministerial-level ASEAN Regional Forum (ARF). (4) Not only is there continuing proliferation of regional organizations, two overlapping regional architectures are also developing at the same time in Asia. One of them is an Asia-Pacific architecture that includes the United States, with APEC as its premier regional body, and narrower East Asian one which excludes the only global superpower with the decade-old APT process as its primary regional body. APEC is the only major body in either architecture not convened by ASEAN. Complicating things further, the three Great Powers in the Asia Pacific are each putting their region-building efforts behind three different regional bodies. China is the major behind the APT process and is funding its Track-II arm and the study for an East Asian Free Trade Area. Japan is the major behind the East Asia Summit and is funding its Track-II arm and the study for an EAS-wide trade deal. The United States has re-engaged with APEC and is pushing the idea of an APEC-wide Free Trade Area of the Asia Pacific. There are thus three different Great Powers, three different regional organizations and three different regional free trade area proposals. Regional organizations work best when they bring all the key regional powers together with common purpose; and not when they divide them. Reforming the EAS, as the newest leaders-led body, is good way to find way out of what could become competing regionalisms, while at the same time ensuring the Summit's future. At the moment, the EAS is not even formal institution but rather an informal forum of participating countries convened by ASEAN for strategic discussion. It lies uncomfortably between the broader idea of an Asia-Pacific region and the narrower East Asia one that it is named after and has institutionally evolved within. Australia, New Zealand and India are clearly more Asia-Pacific countries than East Asian ones. Yet the EAS omits the United States, the trans-Pacific superpower, at the core of the idea of the Asia Pacific as region. (5) Moreover, the EAS, as it stands now, only has tertiary in East Asian community building. ASEAN is recognized as the driving force and the APT process as the main vehicle for East Asian community building. (6) The EAS is relegated to only playing a significant role in this process. (7) This article argues that the expansion of the EAS to include the United States would be beneficial to America's in Asia, China, Japan, India, ASEAN and the process of consolidating the increasingly crowded regional architectures of East Asia and the Asia Pacific while securing the EAS distinct and sustainable future. …